then they school by sex (Cohen 1932). 



Spiny doyfisn are well known for their voracious appetites, ana will eat 

 anything smaller than themselves, including fish, crabs, squids, worms and 

 ctenophores (3igelow and Schroeder 19b3). They have few natural enemies, 

 although large sharks occasionally prey on them (Cohen 1982). 



The total biomass of dogfish in the New England area has been estimated 

 to range between 150, UOU and 225,000 metric tons (Cohen 1982). However, a 

 sustained and extensive fishery would quickly deplete the resource because the 

 spiny dogfish produces few young over a long period of time. 



Bottom Trawl Survey Results 



The cumulative spring and autumn distributions over the time series are 

 shown in Figures 2.1 and 2.2. These plots represent what is known of seasonal 

 spiny dogfish distribution in the Middle Atlantic Bight. The spring 

 distribution shows larger catches generally occurring offshore. The inshore 

 concentration indicated by Figure 2.1 is partially an artifact of the 

 different timing of the two spring cruises as discussed in the section on 

 methods. Figure 2.3 attempts to correct this artifact by deleting all cruises 

 prior to 1976, and is considered a more representative pattern of the spring 

 distribution, with the dogfish inshore south of Delaware Bay but not yet as 

 far north as coastal New Jersey or New York. The autumn distribution (Figure 

 2.2) indicates a southerly movement from northern summer grounds. 



Graphs of mean weight and number per tow are shown in Figures 2.4-2.7. 

 In the spring, catches are consistently larger in the offshore strata sets 



44 



